let n = 'wocao';
let obj = new Object();
Object.defineProperty(obj,'_name',{
    get() {
        console.log('get ->',n);
        return n;
    },
    set(v) {
        console.log('set ->',v);
        n = v;
    }
});
console.log(obj._name);
obj._name = 'pigu';
console.log(obj._name);